When an ejection seat jettisons out of an airplane, it must clear the transparent canopy at the top of the cockpit. Typically, the canopy is removed before the seat is ejected. In the event the canopy is not discharged, or the plane does not have a canopy ejection system, it is desirable to have a seat capable of blasting through the canopy.
It has been found that ejection seats have difficulty penetrating the canopy with the shear force of the seat. Therefore, it is preferable to have the canopy fractured before the seat reaches the canopy. Prior attempts to fracture the canopy, include attaching a detonating cord about the canopy, to break it up when the cord is detonated. Although effective, the attachment of the cord is labor intensive and involves the additional step of detonating the cord before the seat is ejected.
Another option is to mount a spear like member to the top of the seat, that punctures and fractures the canopy when the seat is catapulted upward. The stationary spear relies on the energy of the seat to penetrate the canopy. With the use of thicker bird resistant canopies, it requires more seat thrust to fracture the canopy, with some small seats unable to penetrate the canopy at all. Therefore what is needed is a self-actuated powered canopy breaker that causes the canopy to fracture, before the seat comes in contact with the canopy.